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