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