Okay so a body can tell a lot about a cat. This will be based entirely off the warrior series and things hat are mentioned in the books, as well as my own thoughts, assumptions, and connections.

      A sleek pelt is being well groomed. It can show health, because a sick cat isn't going to groom themselves (especially if they have a fever, when you have a fever you loose even more water than usual because your body is trying to cool yourself down. So grooming would loose even more water and they just wouldn't do it.)

      A glossy pelt is said to show health and being fed properly in the series, which makes sense. Being fed means you get the proper nutrients to have good fur. At least, that's what I'm thinking. No facts to support that so don't quote me on it.

      Webbed paws can be a sign of a swimming clan cat. Webbed paws = boosted swimming skills

     A hard muscled cat or a well muscled cat is a sign of a warrior. Being well-muscled doesn't mean that they have super thick legs, it means they have strong, maybe even defined muscled. Which means it isn't limited to one single clan.

      Broad shoulders can be a sign of a strong cat. ThunderClan cats are almost always broad-shouldered, especially if the Erin's are trying to glorify the cat.

      Having soft muscles can be a sign that the cat is either very young or isn't from somewhere they never had to work for food. Medicine cats might also have softer muscles, but not too soft. They do work very hard.

      Thick fur can be a sign of a cat who belongs to a forest clan. Thick fur makes it easier to get through brambles without tearing your pelt off. Any cat can have thick fur though.

      Being overweight can either mean kittypet or Queen. Most warriors will never get to be overweight since they eat to live, not live to eat.

      RiverClan cats are said to have waterproof pelts. This is kind of self explanatory.

      WindClan cats have thin bodies. A lighter weight will run faster compared to a thick, heavy pawed cat. They're almost aerodynamic bodies.

      ShadowClan are never noted to have any particular signs other than darker fur. Which is kind of... Meh. They should have something special other than evil garbage dump rat-eaters.

       Long legs can be on any cat, but WindClan does tend to have them most. I personally imagine WindClan cats to be similar to oriental cats

Nice.

      I head-canon ThunderClan to typically be Norwegian Forest Cats or a mix. They're super tree guys.

      I head-canon RiverClan to typically be a Main Coon or a mix. They have waterproof coats and tend to have a fascination with water.

      I head-canon ShadowClan as an American Shorthair or really any kind of cat. ShadowClan is really rad and has many different cats in it. It's like America. Melting pot of cats.

      I super head-canon WinClan to typically be Oriental cats or a mix. Long legs, sleek bodies. These would be excellent rabbit chasers.

       Alright that was rad. I'll add to this if do think of more! -Tea