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