Printing with a black filament for the face hides the LED matrix nicely, however I had to turn the intensity up to the max. It is quite visible in a darker room, but can be washed out in bright sunlight.
Note: I did not have any screws small enough for the printed holes on the back, so I first used a 3/32", then a 7/64" drill bit to hollow out the hole further by hand (I didn't actually need the drill). Then I was able to insert some M3 screws I had lying around.
I used Hatchbox black PLA for the face and back panel, and Paramount "Iron Red" for the main body.