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