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