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