Stripes on Tallis states that the Pri Megadim stated that the custom was to use blue in his time (mid to late 1700's). Apparently both customs were extant long before. I saw an article that Yigal Yadin found stripes on taleisim (like today) at Matzada but I lost the reference and do not recall if he mentioned the colors.
Peri Megadim (Eshel Avraham 9:6) writes that the custom was to have
blue stripes on the talis, which came to remind one of the techeiles.
The custom, however, is to have black stripes on the talis. This is
possibly because the ink that the techeiles was made from was black
(See Rambam, Tzitzis 2:8 and 2:2). Alternatively, it is so that people
won’t think that this is actual techeiles.
Peri Megadim explains that although a talis should be the same color
as the strings, the stripes do not constitute a problem, because we
follow the principle color of the garment.
This means that nowadays people can wear differently colored stripes without a problem and that the colors do not have significance.