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)(13,14,20,22,19,23,18,17)(15,24,27,21,26,28,25,16)(5,6)(7,11)(8,10)(9,12)(13,15,19,26)(14,21,23,16)(17,28,22,24)(18,27,20,25)(2,4)(5,7)(6,9)(8,12)(10,11)(13,16,19,21)(14,15,23,26)(17,25,22,27)(18,28,20,24)(7,12)(9,11)(13,17,20,14,19,22,18,23)(15,16,27,24,26,21,25,28)(6,10)(9,11)(13,18,19,20)(14,22,23,17)(15,25,26,27)(16,24,21,28)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.