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