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