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