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