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