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