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