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