Repetition of colour, line and shape make for a clear, defined and easily read design and layout. The rounded shapes give the image a characterised cartoon style and feel. Combined, this creates a high quality vector based graphic.
This design uses primary colors to deliver its purpose. When I saw this design, I was immediately drawn to its color scheme. I think primary colors make up one of the most powerful color schemes, thus making them a huge tool for me as a designer.