At some point you run out of pixels on your screen to visualize it all at once. My suggestion in your case is to not use a graph at the beginning, but rather gr

At some point you run out of pixels on your screen to visualize it all at once. My suggestion in your case is to not use a graph at the beginning, but rather grouping nodes based on metrics. Like degree (group all contacts of a node that only has a single contact), communities, or value (e.g. IP's in a subnet).