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