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