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