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