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