How do I diagram this sentence?

Question

John or Mary was coming.

Answer 1

Single line - 'John' goes there.
Space
Another single line - 'Mary' goes there.

Go to the ends of each line and draw a line slanted toward the middle of the space you left - like a 'V' on its side.

Connect the tips of the 'V' with a line, and on that line put 'or'.

From the point of the 'V', draw a line to the right. On that line,
put 'was coming'.

Between the point of the 'V' and the 'was', put a line perpendicular to and extending on both sides of the line you just drew.

Easier to do than explain.

Answer 2

John - proper noun

or - conjunction

Mary - proper noun

was coming - verb