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