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