This lintel has undergone some damage since Petrie photographed it, so I made a montage of modern photo with overlay of Petrie's photo where the damaged areas were.
Note how visually, the composition has a pyramid effect. The 'sun' of the top element is its apex, and the two corner points are at Set's feet.
After creating the line drawing, I then colored it. I chose gold for the background because of Set's town then, Nubt, aka "Goldtown". I gave his symbolic plant a reddish brown, because I was trying to make it 'sedge' like, (although it might be here as the 'lily'). Also, the reason Wadjet is purple, because she was next to last that I colored, and I was running out of colors. Other than that, I think the colors are pretty true, reddish colors for Set, Was, and Bull; Pure Red for 'heart', and 'love'; Blue for Ankh to suggest blue of Amun.