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