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