If you are playing the GOG version of Witcher 3 with the Steam Controller, you can enable the official Steam Controller icons in the user.settings file. Navigate to the following folder and open the file with your text editing program:

\Users\<username>\Documents\The Witcher 3\user.settings

Under the [Input] section, you will see this:

SteamController=0

Change the 0 to a 1 and save the file. Now when you launch the game it will show the Steam Controller icons instead of the Xbox icons. Keep in mind, you will still have to launch the game from Steam for the controller to function properly. While this is not a huge deal, it is nice seeing the Steam Controller icons in the game. Screenshots are attached so you can see what it looks like in game.