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