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