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