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