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