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