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