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