Microsoft has packed up Visio stencils for creating diagram of server deployments such as SharePoint Server technology. These models are created using Office Visio 2007. You can modify the Visio files to illustrate how you plan to incorporate Microsoft SharePoint Products and Technologies in your own environment.
Ref: http://go.microsoft.com/fwlink/?LinkId=136952
Download this zip file of Microsoft Office Visio stencils to create your own diagrams for models of server deployments.
Cheers!!