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