On February 17, 1986 Greece issued a set of 24 stamps showing the Greek gods of antiquity. There are 12 values issued in both sheets and coil format. This 110 drachma coil stamp (Sc #1553a) from the set depicts Apollo, the greatest master of the lyre with his instrument. In Greek mythology, it was Apollo who taught Orpheus to play the lyre.
From wikipedia, "The lyre of classical antiquity was ordinarily played by being strummed with a plectrum (pick), like a guitar or zither, rather than being plucked with the fingers as with a harp. The fingers of the free hand silenced the unwanted strings of the chord."
Page 15 of this thread includes a 1985 Greek EUROPA stamp showing Apollo with his lyre.