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