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