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