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