Where can I find a wiring diagram for a ih61m Lenovo m/b

Search Google or Duckduckgo or contact Lenovo.

It isn't available to the public, and may not be available at all. Only Lenovo knows what company actually designed and produced it.
Might have been in Thinkcentre M71e systems, among others

It's a desktop pc motherboard for a small system
You do better describing what you are trying to do with it.
It's too old and cheap to repair it if not working.