You could do a few light sets for the muscle your worked the previous day to facilitate blood flow/recovery.
Or if you wanted to get more workouts in during the week, you could also accelerate your split. Instead of a day off between each workout, do 2 on 1 off. Thus Legs - Monday, Back/Shoulders -Tuesday, off, Arms - Thursday, Legs - Friday, off, Back/Shoulders - Sunday, Arms - Monday, etc. etc.
Or if what you are doing is working for you, just enjoy it and keep going until you stall out. Then once your progress stops, try something different.
James 1:16-17 ESV
Do not be deceived, my beloved brothers. Every good gift and every perfect gift is from above, coming down from the Father of lights
With God's help...Mens sana in corpore sano