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