In the latest releases (since v.184.108.40.206) NodeXL allows users to pan, zoom, and scale the network graph in a more refined way.
These new control elements allow for the selection of a set of nodes (arrow), the addition of another set of nodes to the selected collection (arrow with plus), and the removal of a selected set of nodes from the existing selected collection (arrow with minus). In addition the “hand” icon allows the user to move the view pane over network (or move the network beneath the view pane). The mouse wheel still zooms in and out for getting detailed views of small areas of the graph.
These added controls should provide addition flexibility for managing a complex graph.