Would this help? It's not a diagram but lists pinouts.
http://web.archive.org/web/20040426160943/http://developer.apple.com/documentation/Hardware/Developer_Notes/Macintosh_CPUs-68K_Desktop/Mac_LC_575.pdf
http://web.archive.org/web/20040426161834/http://developer.apple.com/documentation/Hardware/Developer_Notes/Macintosh_CPUs-68K_Desktop/Mac_Color_Classic.pdf
http://web.archive.org/web/20040426160943/http://developer.apple.com/documentation/Hardware/Developer_Notes/Macintosh_CPUs-68K_Desktop/Mac_LC_575.pdf
http://web.archive.org/web/20040426161834/http://developer.apple.com/documentation/Hardware/Developer_Notes/Macintosh_CPUs-68K_Desktop/Mac_Color_Classic.pdf