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