If a person is "open" - that usually means they share things about themselves, don't hold secrets too closely, and others may view them as transparent.
If a person is "open-minded", they are "open to" possibilities that may or may not be outside of the "norm" for others. An open minded person is more likely to accept others who think differently. They also are more likely to accept/embrace new ideas and perceptions.
Hope that was helpful! :)