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