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