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