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