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