I take you are talking about PAYG Instalment and not PAYG Withholding. PAYG Withholding becomes a liability when you pay wages and when you pay it at the end of the quarter then the payment goes back to the liability account and hopefully it should zero out.
PAYG Instalment is either Company tax or personal tax based on your guestimated income for the year which you also pay quarterly. I see it as an Expense, line item "Tax on Taxable Income". Just change all the cheques to an expense account.