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