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