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