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