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