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