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