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