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