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