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