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