If you want it to be interactive, you will need to figure out a few things:
1.) how to format the data so it can be streamed off disk. 2.) how to cull the offscreen bounding boxes quickly. 3.) how to cull tiny bounding boxes quickly.
The central problem is finding a way to group the nodes efficiently into chunks. A 2D approach is probably best. You would then have something that could be rendered efficiently.
Other than that, maybe a point cloud renderer? There might be one you can buy off the shelf, or something open source.