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