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