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