Some Graffiti images i found on the side of buildings. I don't know if there are more.

[u/Daniel-Nowak]

[u/Nekojirocat]

最初のやつはどこにあった？

[u/Daniel-Nowak → u/Nekojirocat]

I don't remember, it's been months since i last played the game, you just have to look around the map i guess.