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