The Wikipedia article “Cladogram” explains cladograms this way:

A cladogram uses lines that branch off in different directions ending at a clade, a group of organisms with a last common ancestor.

Thus, a cladogram tells a lot about what we know about the evolution of different species.

The link above starts with Amniota, the narrowest clade that includes both us and our cousins the dinosaurs. The home page, with a link to the root of the tree, is here.