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