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