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