It can have several significances of unfathomable depth and wisdom.
One of them is that the Lord Jesus Christ indicates to the Personhood of the Spirit, for wind cannot wish anything, for it blows automatically, while when "wind" is used metaphorically as referring to the Spirit, it indicates that birth in Spirit is not automatic, but it is based on reciprocation of the born - man - and the Birthgiver - the Spirit, Who blows where He wishes.
Moreover, the wind is not restricted by anything, and so a person who will be born in Spirit will live a new type of life when he will do what he wishes, for the transforming work of Spirit in him will turn him into such a person that desires good things and is no more a moral person, that is to say, a person who restricts his vile desires for the sake of moral laws, but whose vile desires are transformed into desires towards God and His Eternal bliss-creating things, and such a person is already immoral person in a superlative way, because for such there is no Law (Gal.5:23).
Therefore, the sentence "and so with everyone who is born of Spirit" can have this meaning as well: only the Spirit-endowed man is really free and "blows", that is to say, speaks and acts without being influenced by tyranny of fears, sinful passions, earthly/limited interests or rigid ideological mindset; since such a man possesses the Spirit, that is to say the Mind of Christ (1 Cor. 2:16), then his words and actions are strange to the world, ununderstandable and even hateful for the latter. But a Spirit-endowed man is totally free and acts at will, or rather co-acts with his inspiring Spirit, for where is the Spirit of God there is freedom (1 Cor. 3:17).