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