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