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)(23,26)(24,25)(27,28)(1,2,4,3)(6,9)(7,12)(14,18)(16,19)(22,24)(23,27)(1,3,4,2)(13,15)(14,19)(16,18)(17,20)(21,23)(22,26)(24,28)(25,27)(5,7)(6,10)(8,12)(9,11)(13,15)(14,19)(16,18)(17,20)(21,24,25,22)(23,28,27,26)(5,6)(7,10)(8,9)(11,12)(13,16,17,19)(14,15,18,20)(21,23)(22,26)(24,28)(25,27)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.