Hi Kim,
The easiest way is to have Edge reopen your last session automatically.
Open Edge and select Settings > Start > home > new tabs. Under When Edge starts, choose Open tabs from the previous session. Close Edge without manually closing your grouped tabs. Just exit the window. Open Edge again. Your tab groups, names, and colors should be restored exactly as before.
If Edge ever starts clean, press
Ctrl+Shift+Tto reopen the last closed window and bring the previous session back, groups included.
Let me know if this works!