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