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)(25,26,30,31)(27,28,34,35)(29,32,37,38)(33,36,39,40)(1,2,5,6)(3,4,7,8)(10,15)(11,16)(13,22)(20,24)(26,31)(28,35)(29,37)(33,39)(2,6)(3,7)(10,15)(12,18)(17,21)(20,24)(25,27,30,34)(26,28,31,35)(29,33,37,39)(32,36,38,40)(2,6)(3,7)(9,11,14,16)(10,12,15,18)(13,19,22,23)(17,20,21,24)(25,28,30,35)(26,27,31,34)(29,36,37,40)(32,33,38,39)(1,3)(2,4)(5,7)(6,8)(9,12)(10,16)(11,15)(13,20)(14,18)(17,23)(19,21)(22,24)(25,27)(26,28)(29,33)(30,34)(31,35)(32,36)(37,39)(38,40) involution — undirected(1,4)(2,3)(5,8)(6,7)(9,13)(10,17)(11,19)(12,20)(14,22)(15,21)(16,23)(18,24)(25,29)(26,32)(27,33)(28,36)(30,37)(31,38)(34,39)(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.