As the window & door contact from homematic is only available in white & brown (recently also in black), here is a cover for every color you can print.
It is used instead of the original cover.
The button can be left open or, if desired, “extended” with the model offered on the 2nd plate. This should then be printed in transparent, so that the color feedback is still visible. 

It may be that the magnet part (smaller part) needs some double-sided tape between both objects so that it holds. However, this is not visible from the outside.