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