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