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