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