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