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