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