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