To compare a revision, view the page and click the Moderate button
Click the Compare revisions button
Next, select the revisions you would like to compare and then click the Compare button. The live version of the page will be in green and any drafts will be in yellow.
You will see any changes on the page content shown in red as seen below.
Note: Changes to blocks, menu items, or nesting will not be shown in the moderation work flow. Only changes to page content in the editor will be shown.