You can easily plot the output from a FFT as lines with the Arduino IDE and the Serial Plotter feature as we did it here for different sinus tones:
But this is not nice and hard to read.
We used also the Sonic Visualiserer to get FFT data from MP3:
This is an example from Spectrogram.py used in an Adafruit Tutorial.
See more examples in the thread Sound Visualization
We have to investigate if this Grafana plugins can make an appropriate graph from a FFT data output with – let’s say 128 bins! This are 128 singel numbers for one point in time. Each number represents a frequency range.
see also this page with more details and a more fittng example figure: Heatmap Panel | Grafana Documentation