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