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