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