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