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