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