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