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