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