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