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