Agile Waterfalls

The waterfall method is a traditional project management approach that uses sequential phases to define, build, test, and release project deliverables. Each phase is completed and approved before the team moves on to the next phase. The project can't move back to previous phases.

Agile is an umbrella term covering several newer project management approaches that use iterative work cycles, called sprints. Each sprint uses 'mini-phases' to define, build, test, and release the project deliverables.
You show the audience a visual comparing the two methods, which shows how the waterfall method is a sequential process while agile methods are iterative cycles from the beginning to the end of the project.

 It looks like your audience gets the different methods, but diving deeper will be helpful. The main difference between waterfall and agile methods is in the goals; the waterfall method wants to get everything right the first time, and agile methods want to get things released quickly. Differences in adaptability, documentation, testing, and collaboration support different goals. Let's look at each a little closer. 

If we're talking about changing requirements, the waterfall is not adaptable. In fact, the waterfall will force the project team to start a project over if a requirement change is discovered late.
Agile methods are extremely adaptable to changing requirements because of the project reviews and validates the requirements at every sprint throughout the project. So, any change in requirements is simply addressed in the next sprint.
If we're talking about changes to project team members, the waterfall method is very adaptable. Waterfall requires detailed documentation at each step, so getting a new team member up to speed is a matter of reading the documents.
Agile methods are more focused on quickly releasing the deliverables, so documentation tends to be done after. New project team members would have little information in the project's documentation, so it would be harder to get a handle on the project.