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