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)(11,16)(12,17)(13,18)(14,15)(19,23)(20,24)(21,22)(25,26,29,31)(27,32,35,30)(28,36,37,33)(34,38,40,39)(1,2,5,6)(3,7,8,4)(9,11,15,12)(10,16,14,17)(13,20,22,19)(18,24,21,23)(25,27,29,35)(26,30,31,32)(28,34,37,40)(33,38,36,39)(1,3)(2,4)(5,8)(6,7)(10,14)(11,12)(18,21)(19,20)(26,31)(28,37)(30,32)(34,40) involution — undirected(1,4)(2,3)(5,7)(6,8)(9,12,15,11)(10,17,14,16)(13,19,22,20)(18,23,21,24)(25,26)(27,30)(28,33)(29,31)(32,35)(34,38)(36,37)(39,40)(1,2)(3,4)(5,6)(7,8)(9,13,15,22)(10,18,14,21)(11,19,12,20)(16,23,17,24)(25,27)(26,32)(28,34)(29,35)(30,31)(33,39)(36,38)(37,40)(1,4)(2,3)(5,7)(6,8)(9,14,15,10)(11,17,12,16)(13,21,22,18)(19,24,20,23)(25,28)(26,33)(27,34)(29,37)(30,38)(31,36)(32,39)(35,40)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.