One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(5,6)(7,9)(8,11)(10,12)(13,14)(15,19)(16,18)(17,21)(20,24)(22,25)(23,27)(26,28) involution — undirected(5,6)(7,9)(8,11)(10,12)(14,18)(16,24)(19,25)(20,21)(22,28)(26,27) involution — undirected(2,4)(6,9)(7,12)(10,11)(13,15,17,23)(14,19,21,27)(16,22,24,28)(18,25,20,26)(14,20)(16,24)(18,21)(19,26)(22,28)(25,27) involution — undirectedA Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.