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