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