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