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