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