Question about digital modulation
Your unmodulated carrier is a sine wave. When modulated it can look like this: -

 

That's called On-Off-keying (OOK) and very similar to morse code. It could look like a version of OOK called ASK (amplitude shift keying): -



And below is an image of ASK, FSK and PSK: -




  So the symbols can be seen as graphical representations of the
  associated bits?


The words you use do not ring true. Look at the pictures.