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