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