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)(11,13)(12,16)(14,15)(17,21)(18,20)(19,22)(23,24)(25,26)(27,30)(28,31)(29,32)(33,34)(35,40)(36,39)(37,38) involution — undirected(1,3)(2,4)(5,7)(6,8)(12,19)(16,22)(18,23)(20,24)(25,27)(26,30)(28,34)(29,37)(31,33)(32,38)(35,39)(36,40) involution — undirected(10,15)(11,17)(16,22)(18,23)(26,28)(27,33)(32,36)(35,37) involution — undirected(9,11,14,17)(10,13,15,21)(12,18,19,23)(16,20,22,24)(25,28,31,26)(27,34,33,30)(29,36,39,32)(35,38,37,40)(1,3)(2,6)(4,8)(5,7)(9,12)(10,16)(11,18)(13,20)(14,19)(15,22)(17,23)(21,24)(25,29,31,39)(26,32,28,36)(27,35,33,37)(30,40,34,38)(1,4,5,6)(2,7,8,3)(9,13)(10,17)(11,15)(12,20)(14,21)(16,23)(18,22)(19,24)(25,30,31,34)(26,33,28,27)(29,38,39,40)(32,35,36,37)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.