Unless protected from light cauliflower curds do tend to go pink. I've never seen pink leaves though...

I suspect that your cauliflowers are being attacked by root fly. The lack of nutriment and water to the plant, caused by most of the roots having been eaten under the soil, can cause a pinkiness in the leaves before the plant dies. Try scraping down into the soil to expose the roots and look for little white maggots amongst the roots.