What are the similarities between religions (Hindu, Islam, Christianity, Buddhism, Judaism) and Art?

Well all religions, especially the ones you mentioned, have as a central theme the idea of sacrifice. Hence, if I were to visually develop a theme for your project it would be the idea of sacrifice, and how this notion permeates people of all faiths. In Christianity you obviously have the sacrifice of Jesus, which is symbolized today in some Christian denominations by the consumption of bread and wine (i.e. Communion). In traditional Judaism, animals were sacrificed. In Islam, sacrifice is given in the form of alms giving, especially to the poor and for the sake of the Muslim community. In Hinduism sacrifices, ranging from money to food is given to idols, and the same goes for certain varieties of Buddhism. So may be you can visually represent the individual sacrifices that are unique to each religion. I hope that helps.