Go to Users > Capabilities.
On the right hand side, make sure you select “Editor” from the “Select new Role” box, then click “Change” to bring up the appropriate permissions for that role.
Then, you just need to check the first checkbox, which is labeled “Activate plugins.” You might need to check “Install plugins”, “Update plugins”, and/or “Delete plugins” if you want to give your user additional permissions, but the minimum required to see the plugins is to check “Activate plugins.”
This screenshot should help clarify:
