you could get a sheet of any thin metal or plastic for that matter and make a housing to hide the servo.Although it may not fit in with your design. And the metal of what ever you use may add to much weight.
A second optioin it to wrp your servo in contact film or something to hide it.(cheap and quick)
And the third but most expensive option is to buy a sevo that will look good and how you want it to look.
