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