At Wikimedia Commons there is a collection with more than a dozen free cartoon images showing public speakers. Two examples are Charismatic Male Public Speaker Cartoon and Pretty Woman Public Speaker Cartoon. You can find more by searching with the terms Public Speaker Cartoon.
Those images can be downloaded either in the Portable Network Graphic (.png) or Scalable Vector Graphic (.svg) formats. I horizontally rotated them to face to the right, recolored some (with Photoshop Elements) and used PowerPoint to create the two images of Toastmasters shown above. Cartoon images also can be found elsewhere at Wikimedia Commons, like the Clueless Cartoon Man I used as a befuddled speaker by erasing the background.