There are several possible reasons for this:
* Less prominent figure: Midas's story is known, but he's not as central to Greek mythology as figures like Hercules, Orion, or Perseus, who do have constellations.
* Lack of symbolic connection to the stars: His story, while interesting, doesn't readily lend itself to a constellation's depiction.
* Later addition to mythology: The story of King Midas is relatively late in Greek mythology, compared to older figures whose stories were already embedded in constellations.
It's fascinating to think about what a "Midas" constellation might look like! Perhaps a constellation depicting a donkey with golden ears, or a hand reaching for a golden apple, could be a possibility.