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