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