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