each index roll over every 6 months, and the most populars, CDX and iTraxx have been created, if I remember correctly, in 2004 or something along those lines.
So there will be no 10y historical.
I looked around and did find a recent chart, but once again, nothing longterm.
When I had my bloomberg terminal, I used to plot my own spreads.
That thing is a beast of a research tool.
I doubt most users utilize even half of its capabilities.