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