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