If you have "Node IDs in First Row" and/or "Node IDs in First Column" from the Adjacency Matrix section in the Excel Import settings enabled, each imported node will have a custom text property "Node Label" with the appropriate value. With yEd's properties mapper it is possible to define a (multiple) template mapping that assigns each node a "shape" depending on said "Node Label" property.
Alternatively, you can designate a data range in the Node List section of the Excel Import settings to specify all kinds of additional data that will be imported as custom properties and thus may serve as basis for properties mapper configurations. (When using this approach, the custom property storing the ID will not be named "Node Label" though, but either have a generic name like "Node Data 1" or an explicitly set column name.)
