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