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