Of the three categories of citizen mentioned in the Constitution, any of the three may be a Senator. A non citizen cannot be a Senator. Only a natural born citizen or a citizen at the time of the adoption can be President. A naturalized citizen or a non citizen cannot be President.
All that you stated is elementary and obvious from the Constitution, What you have not answered, is what makes the natural born citizen " natural born" as opposed to just a "citizen". A natural born citizen is eligible to be a President, a Senator, or a Representative. But a "citizen" can only be a Senator or a Representative.
What is the difference in qualifications between the two?