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