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