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