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