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