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