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