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