There may be a touch of pre-war racism in the artist's version of Judas' hooded eyes. And that nose! It is huge and hooked, a real "schnozz", supposedly a characteristic of Jews. But, of course, all of Christ's Apostles were Jews, including Jesus himself.
As Bloom says to the anti-Semite in Joyce's Ulysses, "And the Saviour was a jew and his father was a jew. Your God".