I get it that the division of labor has been unfair, and I don't blame you for resenting it.
But the title of your post makes me think that you have a real chip on your shoulder about this that is going to get in your way unless you consciously let it go. I totally understand why you feel irritated about this! But in my own experience, when I find myself using language like "using your guests as free labor" when what we are talking about is family members helping out at a family meal, I know I've crossed into the righteous indignation zone and am grooving on my own martyrdom. We all need to go there sometimes! But it's a poor starting point for getting a positive change.
As almost everyone else has said, the solution is to speak up about it. Don't do it as an airing of grievances or in some indirect manner. Don't make it a test to see if they can guess. Just be clear and nice. You might say to your sister, "You know, I've been feeling like I've been doing more than my fair share of the cleanup. Let's figure out a way to share the load among everyone." And as Toots says, speak up as you go along. "Someone please take up the tablecloth and someone take the folding chairs to the basement -- Thusnelda? Cuthbert?"
I would advise against complaining within your parents' earshot. Grudging help drives me crazy. When my children, even now that they are grown, balk at pitching in (which fortunately they rarely do now), I almost reflexively tell them just to forget it. If your parents always turn to you first, maybe try saying "Okay," and then going and delegating it to someone else.