Why is hexacyanoferrate(II) coloured whereas tetrachlorocadmiate(II) is not, even though both lack unpaired electrons?

$\ce{K4[Fe(CN)6]}$ is coloured whereas $\ce{Na2[CdCl4]}$ is not. Even [Laporte selection rule](https://en.wikipedia.org/wiki/Laporte_rule) would suggest the tetrahedral cadmium complex to have a higher intensity of colour than the octahedral iron complex. Could the difference in color be explained on the basis of only d-d transition, or would you have to invoke charge transfer?


