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