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