Decorating a network graph

What would be visually appealing is if we could convert this monotonic graph into something more informative. For example, if we put the distance numbers on the edges and, depending on the distance, change the length of the edge, that would be really helpful.

Or how about assigning different color codes to each cluster? That way, we can easily spot different regions without following the edges.

We need to do something with the labels too. If we move the distance numbers from node labels and place them on the edges, then we need to show something else on the nodes.

There are so many options that we can use to make the graph more insightful; lets see how to implement the few items mentioned above.

Decorating the edges

We can define two sets of edges for this graph. The edges that connect the root node (Mars) to the cluster centers (water, transport, and safety) should be a little thicker to express the main branches. We can use the width property and set it to 2 (the...