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