One vertex per element, one color per generator, with an edge from x to x·s.
(2,3)(5,6)(7,10)(8,9)(11,12) involution — undirected(1,2,4,3)(6,9)(10,12)(14,18)(15,21)(16,23)(20,24)(22,25)(26,28)(1,3,4,2)(5,7,8,11)(6,10,9,12)(13,14)(15,19)(16,24)(17,20)(18,23)(21,26)(22,27)(25,28)(13,15,17,22)(14,19,20,27)(16,25,23,21)(18,26,24,28)(14,20)(18,24)(19,27)(26,28) 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.