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