Not all ties are the same. Many networks are collections of multiplex relationships: multiple types of ties link the entities in the graph.
NodeXL now (v.1.0.1.120) supports edge styles so that links can have color, width, and style to distinguish their nature in a network visualization.
Edge Styles include: solid, dash, dot, dash-dot, and so on. Use the new Style column on the Edges worksheet to set the style for each edge.