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