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