group coloring nodes

[amorigoye]

I am playing with visualization using visNetwork. I want group of nodes to have the same color.
library(visNetwork)
nodes<-data.frame(id=1:9)
edges<-data.frame(from =c(1,2,3,4,4,3,5,5), to=c(2,3,4,6,8,5,7,9))
I want {5,7,9} to be of same color and {4,6,8} also be of different color.
Your help would be appreciated. Thank you