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