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