Dan,
From Wikipedia:
"On early products (1961–1967), the box art corresponded to what they distributed. The box art was mainly done by Shigeru Komatsuzaki, Yoshiyuki Takani, and others... "Another name that came up is Shin Ueda, who as I understand is one among the early artists.
OOP but available on eBay:

Cheers,
Tat