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)(12,14)(13,20)(16,21)(17,18)(19,24)(22,23)(25,26)(27,34)(28,31)(29,36)(30,32)(33,38)(35,39)(37,40) involution — undirected(2,6)(3,7)(9,11,14,17)(10,15,12,18)(13,19,21,23)(16,22,20,24)(25,27,31,30)(26,32,28,34)(29,35,38,37)(33,39,36,40)(1,3,5,7)(2,4,6,8)(10,12)(11,17)(16,20)(19,23)(25,26,31,28)(27,34,30,32)(29,33,38,36)(35,40,37,39)(1,4)(2,7)(3,6)(5,8)(9,11)(10,15)(12,18)(13,19)(14,17)(16,22)(20,24)(21,23)(25,28,31,26)(27,32,30,34)(29,36,38,33)(35,39,37,40)(9,12,14,10)(11,18,17,15)(13,20,21,16)(19,24,23,22)(25,29)(26,33)(27,35)(28,36)(30,37)(31,38)(32,39)(34,40)(9,13,14,21)(10,16,12,20)(11,19,17,23)(15,22,18,24)(25,30,31,27)(26,32,28,34)(29,37,38,35)(33,39,36,40)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.