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