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