For example the shadowing and reflections. How to add all this and what software to use
What software to use is a hard question. To answer this we would need to know quite much about the context in which you are working and what you know!
The first question you need to answer is do you know how to draw that thing on pen and paper? Why? Well in order for you to do this you need to go through one of several options. If you do not know how to draw then any advice we can give you is totally insufficient. Sure we can say use a 3d modelling application. But that is simply glossing over the fact that in order to effectively use a 3d application for presentation graphics requires you also to know how to draw things.
Next you mention realistic. However again we are glossing over the fact that there is nothing realistic about the supplied MIT course ware illustration. Indeed no 3D application can make the kind of perspective mistakes that the image is doing. Also the image has no shadows and no reflections. All it has is simple gradient shading.
In reality you probably need several software depending on your exact needs. Personally if i would be publishing a similar image I would use probably 2 separate tools. One for the mechanical design and one for publication. Though if you know how to draw in a vector package one software may be sufficient (though not necessarily from a time cost use perspective) if you never need the mechanical design.
I would use whatever mechanical 3D solid cad i happen to have open, or whatever my client prefers and then cleanup in illustrator. But that's probably 2 months of foundational knowledge out for you to replicate.
Others have mentioned the possibility of using 3D or CAD software of some kind. However just going by the diagram itself, I see nothing here to suggest it was created using those kinds of software. In fact, quite the opposite, I see perspective errors which would not be present if 3D or CAD software had been used. This is not to say 3D software couldn't be used, and in any case it would certainly make a better job of it as far as the perspective problems are concerned.
To me, the example you posted looks like something which was drawn using 2D vector software. There are plenty to choose from, for example Adobe Illustrator, CorelDraw, Affinity Designer, or even Inkscape (which is free). Also there is no reason you couldn't fix those perspective errors using vector software if you know how to draw in perspective properly.
I don't see anything in the diagram example which would not be achievable using any of the above software. Of course, 2D vector software still has a learning curve, but probably much less than any 3D or CAD software.
As for shadows and reflections, there are actually none present in that diagram. Almost everything is just simple filled shapes, and the shading of the PVC pipe is a simple gradient.
Here's a very rough example showing what's achievable in Inkscape (and any of the other software I listed). Here I've fixed the perspective problem by setting up some guides and a vanishing point - a very simple kind of perspective grid.
The drawing is a part of a presentation of an idea or structure without being a manufacturing drawing. If you are a beginner you should use a simple enough 3D modelling program for this. It makes the wanted view and plausible shading with zero effort after you have drawn the model.
Your model seems easy. An experienced person gets it ready in a hour. I guess a beginner must work tutorials few days before trying this with all small parts. But the elementary 3D extrusion parts like those in my example are easy. With simple enough 3D program a beginner draws them within the same hour he started.
You can insert also annotations in 3D or export the rendered view to a 2D vector drawing program (Illustrator, Inkscape, Affinity Designer...even PowerPoint or Open Office) and insert lines and texts there.
Purhcase recommendations can here be considered as spamming, but I recommend freeware. Get DesignSpark Mechanical. (=DSM) It's a very useful subset of premium priced commercial program named Ansys SpaceClaim.
DSM is not handy when inserting complex 2D annotations (making 2D drawings is intentionally made slow in the free version), so a vector drawing program is a must. But Simple 3D geometry parts are drawn very fast (forgive the random colors):
The rectangular blocks and the tube are the simplest kind of extrusions, they took about one minute. The binding clip is taken from another drawing. Drawing it from scratch as well as all those small parts and bent wires need some serious practicing.
All parts can also be inserted in a 2D drawing program but it prevents changing the view.
Many mass produced standard parts (nuts, bolts, electric components) are available as ready to insert 3D models. Part sellers keep them available for free. People create 3D models for fun and also to earn some money. There are numerous 3D model marketplaces and free download websites.