Q: I-Cloud will automatically renew my subscription in a few days, and I want to cancel this before it charges me.  I cannot find where to do that

What directions have you been trying ? From http://support.apple.com/kb/HT4874 :

Downgrade your iCloud plan

You can choose a lower-tier storage plan to replace your higher-tier plan (for example, a 10 GB plan to replace a 20 GB plan). The downgrade will take effect on the anniversary of when your storage upgrade was purchased.

iOS 5 or later

1. Go to Settings > iCloud > Storage & Backup.
2. Tap Change Storage Plan.
3. Tap Downgrade Options and enter your Apple ID password.
4. Choose a different plan to use when your current storage plan expires.
5. Tap Done.

OS X

1. Choose Apple () menu > System Preferences, then click iCloud.
2. Click Manage in the lower-right corner.
3. Click Change Storage Plan in the upper-right corner.
4. Click Downgrade Options.
5. Enter your Apple ID password, then click Manage.
6. Choose a different plan to use when your current storage plan expires.
7. Click Done.

Windows

 

1. Open the iCloud Control Panel:
   • In Windows 8.1, go to the Start screen, click the down arrow in the lower-left corner, then click the iCloud app.
   • In Windows 8, go to the Start screen and click the iCloud tile.
   • In Windows 7 and Vista, choose Start > All Programs > iCloud > iCloud.
2. Click Manage.
3. Click Change Storage Plan.
4. Click Downgrade Options.
5. Enter your Apple ID password, then click Manage.
6. Choose a different plan to use when your current storage plan expires.
7. Click Done.

What if you don't want to downgrade - I just want to stop automatic renewal and there is no option to do this.

I have the same question.  No place to cancel i cloud automatic renewal.  How does one do that?

The steps on the page that I linked to should let you downgrade your storage upgrade, including back to just the free storage allowance : iCloud storage upgrades and downgrades - Apple Support - that isn't showing on your iCloud account ?