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