|What a human sees - sharp and coloured|
|What a cat sees - less colour slightly blurred|
The other reason why we don't see colour like you do, is because we are designed to be twilight hunters. Our eyes specialise in low light, where there isn't much colour anyway. They also specialise in motion. If something moves, we notice it. If it stays very very still, like a mouse freezing, it's more difficult for us to see it.
Our vision is a bit narrower and more blurry too.
Twilight is our world.