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