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