I’ve updated the generic icons linked from this page to include a virtual router/switch. I’ve also added two different spine and leaf topologies to the presentation. I may add other “generic” topologies over time, as I run across ones that seem worth including. These are completely public domain; I would encourage you to use them instead of the normal sets of vendor icons in drawing, books, blogs, etc.
Updated: Thanks to Greg Ferro, there is now a version of these in Omnigraffle! They’re linked on the same page.