Microsoft Visio sits well in MS Office environment. It has been around very long time and was already a mature product when Microsoft bought it. Visio and its rivals can handle complex multilevel documentation that is difficult or impossible to be created in vector art drawing programs. Your examples are not that complex.
Here is a half year old collection of commercial software as reviews
Freebies exist, but they are more limited and can easily drop the ride when Windows changes. Here are some:
Open Office is a free suite that is intended to be an alternative to MS Office. There is also something at least good looking against MS Visio.
Addendum: I still have 20 years old pre-Microsoft Visio in use, because it works well in Win7 (in XP mode). Its old fashioned clipart symbols are a little amusing, but no other complaints in simple works.