How to change color of entities shown in Google map?
There's currently no way to achieve this in Google Maps. You can send feedback within the app, so you could suggest that they add such a feature.

There are alternative map apps you might like to try instead. Those based on the free OpenStreetMap database usually allow you to change which tile server to use, which gets you a completely different visualization of the map data: some tile servers are optimized for particular uses, such as cycling or marine navigation.