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