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