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