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)(12,18)(13,14)(15,17)(19,21)(20,23)(22,24)(25,26)(27,36)(28,30)(29,38)(31,35)(32,39)(33,40)(34,37)(1,3,4,7)(2,5,6,8)(9,11,15,14)(10,16,17,13)(12,20,22,19)(18,23,24,21)(25,27)(26,32)(28,37)(29,40)(30,38)(31,39)(33,34)(35,36)(1,2)(3,5)(4,6)(7,8)(10,17)(11,14)(18,24)(19,20)(25,28,31,40)(26,33,35,30)(27,37,39,29)(32,34,36,38)(1,3)(2,5)(4,7)(6,8)(9,12)(10,18)(11,19)(13,23)(14,20)(15,22)(16,21)(17,24)(25,29)(26,34)(27,28)(30,32)(31,37)(33,36)(35,38)(39,40) involution — undirected(1,2)(3,5)(4,6)(7,8)(9,13)(10,11)(12,21)(14,17)(15,16)(18,20)(19,24)(22,23)(25,27)(26,32)(28,37)(29,40)(30,38)(31,39)(33,34)(35,36) involution — undirected(9,14,15,11)(10,13,17,16)(12,20,22,19)(18,23,24,21)(25,30,31,33)(26,28,35,40)(27,38,39,34)(29,32,37,36)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.