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