If you open one of the Data Model PDFs listed at the bottom, there are links there
Which one did you open? Most of them I looked at don't have the Design Templates links, or at least the links to Visio templates.
The overall problem with the Data Models is that they are just that, data models. The OP wants templates/shapes for system or IT models.
I used the attached stencil that I created for the images in this help article. Maybe they'll serve as a start.
Thank you Jonathan Quinn
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