The only extant description on Attila's appearance is that of Priscus: "short of stature, with a broad chest and a large head; his eyes were small, his beard thin and sprinkled with gray; and he had a flat nose and a swarthy complexion, showing the evidences of his origin" (like this old illustration shows).
However when I search for images of Attila, nearly all of them have Caucasoid features.
Is there any evidence that he was "Caucasian" looking?
Just made a quick image search, and the majority of what came up were actually oriental.
Attila was not a Caucasian man, and the only explanation I can think of for his depiction as such aside from eurocentrism is the nature of Huns being more of a confederation than a single, isolated group. While the ruling class spoke a Turkic language, Huns as a whole did include a number of Indo-European nations.