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