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