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