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