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