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