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