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