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