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)(15,17)(16,18)(19,20)(21,22,25,27)(23,24,28,26)(2,4)(5,7,9,12)(6,10,11,8)(13,15,18,20)(14,19,16,17)(21,23,25,28)(22,26,27,24)(1,2,3,4)(6,11)(8,10)(14,16)(15,20)(21,22,25,27)(23,26,28,24)(5,8,9,10)(6,7,11,12)(13,16,18,14)(15,19,20,17)(21,22)(23,26)(24,28)(25,27)(5,7)(6,8)(9,12)(10,11)(13,17,18,19)(14,15,16,20)(21,24,25,26)(22,23,27,28)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.