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