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