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