Graph visualization: how to generate ForceAtlas2 layout with square border

Question

I'm trying to reproduce the example graph visualization (see below) from this blog. I am using Python and cugraph.force_atlas2 from RAPIDS to generate the ForceAtlas2 layout. The problem is that no matter how I adjust the parameters, the vertices are always laid out in a roughly round shape. However, in the example graph viz, the vertices are clearly bounded within a square. I would like to know how this could be done. Are there any transformations or parameters I am missing? Thanks.

My typical call of cugraph.force_atlas2 is like this:

cugraph.force_atlas2(G,
                     max_iter=500,
                     pos_list=None,
                     outbound_attraction_distribution=True,
                     lin_log_mode=False,
                     edge_weight_influence=1.0,
                     jitter_tolerance=1.0,
                     barnes_hut_optimize=True,
                     barnes_hut_theta=1.0,
                     scaling_ratio=2.0,
                     strong_gravity_mode=False,
                     gravity=1.0,
                     verbose=False,
                     callback=None)