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