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