anything goes as far as how topological aliens might choose to represent themselves, but if they were going for something like a proper "translation" of their appearance into metric terms, the relatively obvious approach that jumps out would be to represent them as clouds of nodes and connections (or "vertices" and "edges") like in diagrams (graphs) of social networks or the internet. alternately, or at the same time, you might also represent them like Venn diagrams, drawing borders around clusters of nodes that are related in some way.
as you can see these graphs look kind of... well, like graphs, but there's no particular reason they have to. this is kind of just an extreme "wireframe" view or "exploded" view of the "geometry" of a topological space, perhaps you could say, which doesn't necessarily convey much about what it's intuitively like to be part of these networks.
what our visualization would more concretely look like for any given being depends heavily on your choice of analogies for whatever specific physical laws operate upon the topological world in question. perhaps you could bundle sections of the network together into more "solid" looking forms and coloring / "lighting" them depending on vaguely analogous relationships between nodes, under their physical laws. bundles of spatial nodes could also move around, and things can move through them.
