We can draw lines to connect shapes in Cacoo, but do you know there’s a difference between a line joining at the shape’s perimeter versus joining at the center?
Let’s see how they differ:
When a line joins a point at the shape’s perimeter, it will stick to the point. (As we can see in the above image on the left.)
However, if the line joins the shape’s center, it sticks to the center, and thus, when we move any of the shapes, the line seems to move accordingly without crossing over the shape.
So, depending on your needs, you can choose to use either method of connecting shapes in your diagrams.
Using center-joining lines in mind maps
We recommend using center-joining lines for mind maps. Because it creates a more responsive/versatile look with a web-like effect to the connected shapes. 
I hope you like this tip.
Have fun diagramming! 
Also, how do you usually draw lines to shapes in your diagrams?
Let us know in the replies below!