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