Improve network graph

Before
![network-graph-2-before](https://f.cloud.github.com/assets/72138/89908/c48d70d4-655b-11e2-8a56-0a6647d0bb82.png)

After
![network-graph-2-after](https://f.cloud.github.com/assets/72138/89910/c7e9d5d8-655b-11e2-915f-5c86ee1d92e0.png)