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