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