One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,7)(4,6)(5,8)(9,10)(11,17)(12,20)(13,16)(14,19)(15,21)(18,23)(22,24) involution — undirected(1,3,4,8)(2,5,6,7)(11,18)(12,21)(15,20)(17,23)(25,26,30,33)(27,34,36,39)(28,32,29,37)(31,38,40,35)(9,11,12,19,13,18,21,24)(10,14,15,17,16,22,20,23)(25,27,30,36)(26,31,33,40)(28,35,29,38)(32,39,37,34)(2,6)(5,7)(25,28,30,29)(26,32,33,37)(27,35,36,38)(31,39,40,34)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.