Too Long; Didn't Read
The most effective way to communicate your design is to diagram on a whiteboard the design that you’re verbally explaining. It's one of the most high-signal interviews, because it’s open-ended, which presents more opportunities for both mistakes and flexes. The focus should be on simplicity, thoroughness, and cleanliness, and simplicity. Don't try to rush to completion, giving a thoughtful answer when they've specifically asked about something is a very positive signal.