Does the Bar exam for law school graduates differ by state?

The Bar does vary by state. However, none are easy, and in order to practice law in a state without a hired council, you must pass that state's bar. Therefore you should take the bar in whichever state you are planning work in. If you don't pass the Bar after multiple tries, then you are either studying wrong or shouldn't be in law

States have different exams because they include the state law, which varies from state to state. If I were a guessing man, I would say Hawaii's would be one of the more straight forward since they've only been a state since 1950ish and haven't had a lot of time for random strange laws to be passed, and by the time the states got around to 50, surely some one had an idea how to finagle a constitution. You have to practice the state's bar to practice law in that state. A person is not limited to the number of attempts on the Bar in Kansas, I'm not sure if that varies state to state.

They do vary by state. I live in NV but am really close to CA, my dad's friend who is a lawyer took and passed the bar in both states so that he could practice in both.

You do have to pass the bar, and you can retake it if you fail.