There is no simple answer to this question as every guy is different and will have different preferences. Some guys may prefer natural beauty while others may prefer makeup, and still others may not have a preference either way. It really depends on the individual guy and what he is attracted to.
Generally speaking, however, it is safe to say that most guys do tend to prefer natural beauty over makeup. This is because makeup can often times look overdone or fake, whereas natural beauty looks more real and genuine. Additionally, guys tend to like when a girl looks like she takes care of herself and her appearance without needing to rely on heavy makeup products.