Biblical coloring pages, including one for Noah's Ark, are available online from Gospel Folio Press, at Shop.GospelFolio.com. To avoid the cost and the wait for online shipping, it is possible to find similar coloring pages at a local Christian bookstore.
Local Christian bookstores usually have children's sections that carries children's Bibles, books, gifts and coloring books. A low-cost alternative to purchasing coloring books is to visit Coloring.ws/Christian to download pages of coloring sheets to print out. An additional source for free or low-cost coloring sheets is Google Images, which offers the ability to filter for ones that are free to use.