Large-scale shell-model calculations for the even-even cadmium isotopes Cd-98-Cd-108 have been performed with the ANTOINE code in the pi(2p(1/2); 1g(9/2)).(2d(5/2); 3s(1/2); 2d(3/2); 1g(7/2); 1h(11/2)) model space without further truncation. Known experimental energy levels and B(E2) values could be well reproduced. Taking these calculations as a starting ground we analyze the deformation parameters predicted for the Cd isotopes as a function of neutron number N and spin J using the methods of model independent invariants introduced by Kumar [Phys. Rev. Lett. 28, 249 (1972)] and Cline [Annu. Rev. Nucl. Part. Sci. 36, 683 (1986)].