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