Visualization of graph data is incredibly challenging, particularly when it comes to extremely large, scale-free graphs and social networks. A few simple searches on the Web and you will find some mesmerizing and very cool images. Perhaps the most cited...
K.Ramya, S. Rajakumari, and D. Nalini. International Journal on Recent and Innovation Trends in Computing and Communication, 3 (3):
1338--1343(March 2015)