#1MinuteTip Salesforce now provides “Diagrams Kit of Parts” which is a reusable set of components to help you build, customize, and reuse diagrams. These resources represent the basic parts of a common, standardized visual language for Salesforce diagrams. This has been made available in Google Slides & PowerPoint format.
Though this kit has quite limited number of diagrams as of today, I am hopeful that Salesforce is going to keep adding and enhancing the kit continuously.
For more information and to download these diagrams, please navigate to URL https://architect.salesforce.com/design/diagram-templates/kit-of-parts/

Your link to the template downloads is fine. But the template downloads on Salesforce site seem to be broken. Does it work for you?
Hi David, looks like the PPTX link is not working. I can access the Google Slide link. What you can also do is access the Google slide and download it in pptx format. Hopefully, Salesforce will fix this soon.