There is no difference grammatically speaking but I think that most native English speakers prefer the gerund (swimming) to the infinitive (to swim). There is no difference in meaning between "like to do" and "like doing" but sometimes there is a preference for using one or the other depending on the words that follow.

I like to do and I like doing mean the same thing. Go to swim ... The only example I can think of would be something like: Why do you go to the beach? Oh, I go (because) to swim in the ocean. or Why do you go to the gym? They have a pool so I go (because) to swim. I'm going to swim means you are going to swim right now in this very moment or something you were going to do in the past or will do in the future.

Obviously, since I don't speak Chinese. My answer will be in English. Without giving a long lesson in grammar, let's look at how the language is actually used. Where are you going? (Why are you leaving?) I'm going to go swimming. (I'm going swimming [at the beach, in the pool.]) To go = to leave, depart swimming = the activity I'm going to go swimming. I'm going to go skiing. I'm going to go horseback riding. I'm going to go = I am leaving to do an activity. going = will I will go swimming later this afternoon. I will go skiing tomorrow at the resort. ---------------------------------------------------------------------------------------------- To do, the infinitive form: This is what I like to do. These are the things I like to do. Examples: 1. I like to cook. 2. I like to read. 3. I like to play video games. Notice with like that we often use the infinitive to say what it is we like. Doing. I like doing things for others. = Activity: helping I like helping others. In this case, "doing" is an activity like swimming or running or reading. The things I like doing from time to time are: Reading, swimming, and talking to my friends. 1. I like cooking. 2. I like swimming. 3. I enjoy reading. What are you doing? (What activity are you involved in?) I'm watching television. I was washing my clothes. I'm cooking dinner. I'm busy. (Don't bother me.) These are things I like doing from time to time.

Thank you very much!