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