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