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