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