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