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)(14,16)(15,23)(17,19)(20,27)(21,22)(24,28) involution — undirected(5,7,8,11)(6,9,10,12)(13,14,19,22,18,21,17,16)(15,20,26,27,23,28,25,24)(6,10)(9,12)(13,15)(14,20)(16,24)(17,25)(18,23)(19,26)(21,28)(22,27) involution — undirected(2,4)(13,16,17,21,18,22,19,14)(15,24,25,28,23,27,26,20)(15,23)(20,28)(24,27)(25,26) involution — undirectedA 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.