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