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