Work with the kids to list the qualities of a saint. (Expect the words to reflect their age group.) E.g., Holy, Kind, Humble, Respectful, Obedient, Loving, Caring, Brave....
Then ask them to think of someone they know that has these qualities. (They can draw pictures of these people if you'd like.) Remind them saintly qualities can be in themselves, their friends, their teachers, their priests, etc. They can be people who are real or imaginary (think Spider Man!), dead or alive.
For older kids -- If choosing not to draw pictures of people, ask them to come up with graphic symbols to represent a saintly quality. (E.g. -- Humble = simple bowed head; Loving = decorated heart; Brave = police badge shape.)
Post pictures (symbols or people) with words on a bulletin board or make a poster.
Suggestion: use Wordle.net to make a cool layout of the listed qualities. See my version, Qualities of a Saint
for an example.