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