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