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