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