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