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