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