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