  Signal analysis on graphs relies heavily on the graph Fourier transform,
which is defined as the projection of a signal onto an eigenbasis of the
associated shift operator. Large graphs of similar structure may be represented
by a graphon. Theoretically, graphons are limit objects of converging sequences
of graphs. Our work extends previous research aiming to provide a common scheme
for signal analysis of graphs that are similar in structure to a graphon. We
extend a previous definition of graphon Fourier transform, and show that the
graph Fourier transforms of graphs in a converging graph sequence converge to
the graphon Fourier transform of the limiting graphon. We then apply this
convergence result to signal processing on Cayley graphons. We show that
Fourier analysis of the underlying group enables the construction of a suitable
eigen-decomposition for the graphon, which can be used as a common framework
for signal processing on graphs converging to the graphon.
