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