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