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