Create, read and write GEXF (Graph Exchange XML Format) graph files
  (used in Gephi and others). Using the XML package, it allows the
  user to easily build/read graph files including attributes, GEXF
  viz attributes (such as color, size, and position), network dynamics
  (for both edges and nodes) and edge weighting. Users can build/handle
  graphs element-by-element or massively through data-frames, visualize
  the graph on a web browser through "sigmajs" (a javascript library)
  and interact with the igraph package.

  WWW: https://cran.r-project.org/web/packages/rgexf/