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