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