Here is one possible schedule:
S1 S2 S3 S4
(A B) (H J) (E I) (---)
(C F) (B H) (A E) (D G)
(D I) (F J) (B G) (A C)
(E J) (D H) (C G) (A F)
(B D) (F I) (---) (E G)
(B E) (A G) (C H) (I J)
(G J) (C E) (D F) (H I)
(A I) (B C) (D J) (G H)
(A H) (---) (C J) (E F)
(E H) (G I) (A D) (B F)
(F G) (A J) (B I) (C D)
(C I) (D E) (F H) (B J)
The main issue is that the number of games to play (45) is not divisible by 4. Therefore 12 weeks are necessary and so there must be 3 occasions when a sheet is left empty; above these are in rounds 1, 5 and 9, but let me know if you would like some other arrangement. Teams should play either 2 or 3 times on each sheet.