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