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