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