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