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