Assuming the title of your shortcut is “Open Today’s Note”, the link to open it is:
shortcuts://run-shortcut?name=Open%20Today%E2%80%99s%20Note
You can’t have spaces in links. So those must be replaced with %20. The apostrophe is also replaced by %E2%80%99.
You can also just rename the shortcut to a single word like “today” and then the link is:
shortcuts://run-shortcut?name=Today
To speed things up, I added my Today link as a text replacement entry so anytime I need to add it, it’s just a few keystrokes away.
Do be aware that you are committing to whatever you title the shortcut. Changing the name of the shortcut means you would also have to change all of those links.