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