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