Her genealogical sketch is here.
From Wikimedia.
Lady Elizabeth wears a large asymmetrically draped English hood and a plain dress with probable lower puffed sleeves in this 1536 portrait.
Keywords: 1536, Holbein - Hans the Younger, Elizabeth Cheney, Elizabeth Vaux, Lady Vaux, English, English hood, jeweled headdress, square neckline, long sleeves, necklace