Happy new year! You can find my possible books about diagramming:

Diagram Blending: Building Diagram Networks (Introduction)

https://medium.com/call4/diagram-blending-c9b90682269

Diagram Blending: Building Diagram Networks (Table of Contents)

https://medium.com/call4/diagram-blending-toc-2a73c4fdafc

Diagramming as Practice (Book, version 1.0)

https://medium.com/call4/diagram-as-practice-book-version-1-0-ca31f8a35bb9

and

Diagramming as Activity

https://www.activityanalysis.net/diagramming-as-activity/

Last year, a friend of mine asked a similar need to learn my diagramming skills. It is hard for me to develop a course for it. I always connect Concept and Diagram together.

Send me an email at Swordi @ Gmail dot com if you want to discuss it further.