There is no direct Bible verse that states Adam and Eve, or any other human being, has ever seen God.  There is a direct Bible text that states No man has ever seen God. "No man has seen God at any time; the only begotten Son which is in the bosom of the Father, He has declared Him." John 1:18.

The account of Adam and Eve in Genesis says they 'heard him walking in the cool of the evening….'  Apparently, they were accustomed to communicating directly with God in some way, but they never actually saw God. 

Moses asked to see God and the very interesting narrative in Exodus 33:17-23 explains what happened:

“ The Lord said to Moses, ‘I will also do this thing of which you have spoken; for you have found favor in My sight and I have known you by name.’ Then Moses said, ‘I pray You, show me Your glory!’ And He said, ‘I Myself will make all My goodness pass before you, and will proclaim the name of the Lord before you; and I will be gracious to whom I will be gracious, and will show compassion on whom I will show compassion.’ But He said, ‘You cannot see My face, for no man can see Me and live!’ Then the Lord said, ‘Behold, there is a place by Me, and you shall stand there on the rock; and it will come about, while My glory is passing by, that I will put you in the cleft of the rock and cover you with My hand until I have passed by. Then I will take My hand away and you shall see My back, but My face shall not be seen.’”

God is the Great Creator of all things and is vastly superior to human beings in every way. Man simply cannot see God and live.  Isaiah 55:8-11 gives us a glimpse into God’s vast superiority, “ ‘For My thoughts are not your thoughts, Nor are your ways My ways,’ declares the Lord. ‘For as the heavens are higher than the earth, so are My ways higher than your ways and My thoughts than your thoughts. For as the rain and the snow come down from heaven, and do not return there without watering the earth and making it bear and sprout,

and furnishing seed to the sower and bread to the eater;

So will My word be which goes forth from My mouth;

It will not return to Me empty, without accomplishing what I desire,

and without succeeding in the matter for which I sent it.’ ”