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