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