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