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