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