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