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