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