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