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