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