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