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