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)(11,19)(12,23)(13,18)(14,15)(16,22)(17,21)(20,24)(25,26,30,33)(27,31,35,29)(28,32,38,40)(34,39,36,37)(2,5)(6,7)(9,11,15,22)(10,16,14,19)(12,20,21,13)(17,24,23,18)(25,27)(26,31)(28,34)(29,33)(30,35)(32,39)(36,38)(37,40)(1,2)(3,6)(4,5)(7,8)(10,14)(12,21)(13,20)(16,19)(25,27,30,35)(26,31,33,29)(28,36,38,34)(32,37,40,39)(1,3)(2,6)(4,8)(5,7)(9,12)(10,17)(11,20)(13,22)(14,23)(15,21)(16,24)(18,19)(25,27)(26,31)(28,36)(29,33)(30,35)(32,37)(34,38)(39,40) involution — undirected(9,13,15,20)(10,18,14,24)(11,21,22,12)(16,23,19,17)(25,28)(26,32)(27,34)(29,37)(30,38)(31,39)(33,40)(35,36)(9,14,15,10)(11,19,22,16)(12,23,21,17)(13,24,20,18)(25,29,30,31)(26,27,33,35)(28,37,38,39)(32,34,40,36)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.