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