Jack Ryan (who is President of the United States in this book) and Daryaei do not actually meet in Executive Orders. They did meet once before, at a time when Ryan was not yet president. This was in Clancy’s The Sum of All Fears.
In The Sum of All Fears, Ryan is working at the CIA. It is in this capacity that he meets with Daryaei. The two men meet in Saudi Arabia, just before the terrorists are to be executed for detonating the nuclear weapon in Denver. Daryaei is mainly interested in meeting Ryan because he has heard that Ryan helped to prevent President Fowler from destroying Qom, where Daryaei was living in retaliation for the terrorist attack.
In Executive Orders, Ryan and Daryaei do not meet. Ryan’s Secretary of State does meet with Daryaei, but Ryan himself only meets the Ayatollah in The Sum of All Fears.