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