Its curvy and the middle bits dont connect like they should.
It's there; the emblem to the right.
You can see it on the secret ending.
I have gone through the secret ending video pretty much frame by frame and I have never had a good look at the symbol on the keychain. The best view I got was seeing two or three prongs. It probably is that symbol next to the diagram but as far as I know we dont get a good look at it.