In a standard graph, nodes float in space. In a tree, you usually imagine gravity pulling everything down from a root node at the top.
This vertical layout makes parent-child relationships clear. The root is at the top, its children below it, their children below them, and so on. Leaves hang at the bottom.
It helps you think about depth, height, ancestors, and descendants. When you draw a tree this way, the structure becomes intuitive and easy to reason about.