What do you mean by a template? Are you looking for a high-quality logo image? Those are found here:
There are a series of power point you can use here
Presentations about wikitree topics
Hope this helps if there is not one you want to use you can always mix them up a bit to create one you feel gives folk an overview.
Also review the Youtube Video's created by a member about wikitree.
Add your presentation date to the calendar you will find on the Ambassadors project page
Hope this helps Good Luck