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