You need to understand that the drawings were done by people who
based their drawing from their understanding of what prayer is. No
different from the attire of Jesus, or the face of Jesus itself -
which is quite incorrect as the person depicted is typical
Caucasian whereby Jesus is a Jew living in the Middle East. The
skin color and feature is more likely to be darker and
harsher.
Here is NOT to say that kneeling and clasping of hands and closing
of eyes is wrong. This stance emphasizes the humility and the
hopelessness of the person praying. Some might event prostrate
themselves on the floor, up to the person lah.