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