There is a fabulous graphing velcro mat by Carson Dellosa. It is divided into grids and comes with graphing categories, pictures, and colored squares. I hooked it to the wall and try to do a new graph each week. Carson Dellosa also has this velcro mat in the shape of a piggy bank for learning money, a color mat, an alphabet mat, and a weather mat. I bought them all and use the weather mat with the weather bear with my calendar time.
Children take one object and, depending on the graphing topic, place it in the correct stack.
It is very exciting for them when they see the graph being built up. A math workshop I attended suggested using connecting cubes for graphs as part of the morning routine. Students might come in and place a cube in front of 1 of 2 books they wanted to hear at story time. Or they could be used to choose between 2 types of snacks. Not only does this create a simple graph but the children also get to be involved in some classroom decision making.