This is not a typical Lely portrait so it would be useful to know the date. The face shows character not seen in Lely’s numerous society portraits and she is looking over her shoulder instead of being seated or reposing while facing the viewer.
From Wikimedia.
Sophie wears a straight coiffure with curls on the sides - something like a hurluberlu coiffure - in this Lely portrait.
Keywords: Lely, Sophie von der Pfalz, Kurfurstin Brunswick-Lüneberg, Electress of Hanover, Wittelsbach family, Welf family, Windsor family, Princess, German, proto-hurluberlu coiffure, headdress, jeweled puffed sleeves, necklace, wrap