Basically you need 2 more Property nodes if you want to keep your headers color.
you must do what QueueYueue said first.
Then :
Active Cell.Active Column Number = -2 (this selects all columns)
Active Item.Row Number = -1 (this selects the column headers)
Active Cell.Background Color = Desired color
Then :
Active Cell.Active Column Number = -1 (this selects row header)
Active Item.Row Number = -2 (this selects all rows)
Active Cell.Background Color = Desired color