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