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)(13,14)(15,18)(16,20)(17,19)(21,25)(22,27)(23,26)(24,28) involution — undirected(2,3)(6,9)(10,12)(13,15,17,23)(14,18,19,26)(16,21,24,22)(20,25,28,27)(1,2,4,3)(5,7,8,11)(6,10,9,12)(1,3,4,2)(15,21)(16,24)(18,25)(20,28)(22,23)(26,27)(6,9)(10,12)(14,19)(18,26)(20,28)(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.