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