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