Baby animals are cute, at least in mammals, to prevent infanticide by the parent. So the baby looks 'cute', i.e. not threatening to the parents, so that parents will have empathy and care for it rather than killing a drain on resources. Why reptile babies, having little parental care, look so cute to us is probably the same instinct being projected onto the lizard.
Now, the real interesting question is-do baby lizards know they are cute?