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