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)(15,19)(16,23)(17,26)(18,21)(20,24)(22,27)(25,28)(6,10)(7,11)(13,15,18,17)(14,19,21,26)(16,22,25,24)(20,23,27,28)(6,10)(9,12)(13,16,15,22,18,25,17,24)(14,20,26,28,21,27,19,23)(1,3,4,2)(13,15,18,17)(14,19,21,26)(16,22,25,24)(20,23,27,28)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.