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