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