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