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