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