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