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