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