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