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