Graphviz itself provides a solution for rendering large graphs.
Namely, Graphviz includes sfdp, a multiscale version of fdp (also in graphviz, similar to neato) for the layout of large undirected graphs which has been useful for drawing large graphs (70k nodes, 500k edges) in my project.
You can find documentation for this software on the graphviz web site itself at http://www.graphviz.org/
For more information, here is Efficient and high quality force-directed graph drawing, a paper by Yifan Hu describing the underlying techniques and examples:
http://yifanhu.net/PUB/graph_draw_small.pdf
And a web archive version: https://web.archive.org/web/20210812011222/http://yifanhu.net/PUB/graph_draw.pdf