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