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