Hi, all parameters calculated by the networkanalyzer are available as nodes attributes. So you can select the hubs, e.g based on degree (), by using the select tab dexcribed here:
http://manual.cytoscape.org/en/stable/Finding_and_Filtering_Nodes_and_Edges.html#filters.
Use CTRL + 6 or Select>Nodes>First Neighbours of... to select their neighbours.
If you're satisfied with the selection you can add a node attribute in the data table, use the + button above the table.
Assign a value to all nodes selected and that value can be used to color your nodes in the style panel. See illustration attached.
Hope this helps,
Piet