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