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