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