Images above and on the right were created using computer program Jenn 3D which can draw graphs of finite Coxeter groups on four generators. Jenn builds the graphs using the Todd-Coxeter algorithm, embeds them into the 3-sphere, and stereographically projects them onto euclidean 3-space. The models really live in the hypersphere so they looked curved in our flat space.
Jenn 3D is licenced under version 2 of GNU public license. You can download executable file from developer's site. Unfortunately, developer does not provide executable for Windows platform at present, but he says you can download the source and compile it yourself.