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