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