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)(14,18)(15,19)(20,24)(21,26)(22,25)(27,28)(6,9)(10,12)(13,14,17,18)(15,19,22,25)(16,20,23,24)(21,26,27,28)(13,15)(14,19)(16,21)(17,22)(18,25)(20,26)(23,27)(24,28) involution — undirected(1,3,4,2)(13,16)(14,20)(15,21)(17,23)(18,24)(19,26)(22,27)(25,28)(5,7,8,11)(6,10,9,12)(16,23)(20,24)(21,27)(26,28)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.