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)(16,24)(20,27)(23,26)(25,28) involution — undirected(1,2)(3,4)(6,10)(11,12)(13,14,18,22)(15,21,17,19)(16,25,24,28)(20,26,27,23)(2,4)(13,15,18,17)(14,19,22,21)(16,23,24,26)(20,25,27,28)(2,4)(5,7,9,8)(6,11,10,12)(13,16,18,24)(14,20,22,27)(15,23,17,26)(19,25,21,28)(5,8,9,7)(6,11,10,12)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.