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