Why would a sense of beauty be related to natural truth? Well, say that everyone is born with a randomly assigned set of aesthetic preferences. The people whose aesthetic preferences just so happen to align with a theory that's about to be discovered will be more likely to guess at it in advance, and they will have lots of career success once experiments confirm those guesses. This selects after the fact for people whose aesthetic preferences are luckily aligned with future discoveries. Anyone who prefers the aesthetics of bad theories over good ones will either waste their time or switch to a different field, and nobody will care what they thought was beautiful at the time.

In the end, when it comes time to vote on which theories are beautiful, the theorists who thought that the best theories were beautiful will say "I always thought it was beautiful," and everyone will listen to them because their randomly assigned bias towards the good theories would have led them to respected positions. The ones who always disliked the good theories will not be around, or will have a less respected voice.

That's my theory for how the word "beauty" gets preferentially assigned to good (as in true) theories. One implication of this theory would be that even though claims of beauty tend to align with known-true theories, they aren't useful for telling in advance which theories are going to be true: the people whose preferences have randomly attached them to the bad theories today won't be silenced until the experiments come out.