[igraph] how to modify vertex density

[Song Li]

Hi Gabor,

I have another question when I plot my graph. There are two many 
vertexes(about 200 nodes) in my graph which makes vertexes very close 
together. Can I modify the diameter of graphy or set the distance of 
vertexes lager in order to make the graph looks better?

here is my plot function:
plot(G, vertex.size=8, 
vertex.label.cex=0.7,edge.arrow.size=0.3,layout=layout.fruchterman.reingold)

Thank you.

Sky li