I've always considered the people in the story to be one entire unit with very little distinction. There are some exceptions. Mr. Summers stands apart because he is in charge of the proceedings. Old Man Warner stands out because of his age and out spoken opinions about other towns stopping the lottery. The Adams stand out, because they seem to subtly disapprove of the lottery. Lastly, Tessie Hutchinson stands out because she seems to be so flustered by today's lottery.
Mrs. Hutchinson came hurriedly along the path to the square, her sweater thrown over her shoulders, and slid into place in the back of the crowd. "Clean forgot what day it was,"
I went back to the text and checked for further character differentiation, and I found a few more examples. The story begins by telling the reader that the boy children are all present and gathering stones. Perhaps Jackson is hinting at young male animal instincts. Next the young girls are discussed. They stand off to the side and chat among themselves. The men begin to gather next, and they show up in work clothes, and they are talking about work. It helps the reader think that the lottery is nothing special. The adult women are discussed last, and they too are wearing regular everyday clothing.
I guess you could say that Jackson differentiates characters based on age and sex.