This article will show you how to set up colour coding for the category of a sales order.
First, go to Settings > Modules > Sales Order/Invoices/Credits and tick the ‘Enable sales order category colours’ box.
You can then select the ‘Setup status colours’ to select the colours for your category. Once done click ‘OK’.
Now go to your sales order list and you will see the colours under "Category".
This was added in update v4.344.