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