Let's add another view into the mix, through the view of color theory. Color can set our mood, helps us make decisions and can even spur or curb our appetite. In the magical world, color is used as a main component of spell work such as in the selection of candle colors. Since witches use color for magic and since color is tied into nature, why can't we use the color wheel as a starting point for the directions of the pentacle?
The primary (foundation) colors are red, yellow and blue. This makes sense in the magical world since fire, air and water come together to make up the earth. Secondary colors are green, orange and purple. Green represents the earth, orange is the traditional color of centeredness and creativity and purple is spirit.
Red (Fire) + Blue (Water) = Purple (Spirit)
Blue (Water) + Yellow (Air) = Green (Earth)
Yellow (Air) + Red (Fire) = Orange (Centeredness)
A color wheel represents all colors and their relationship to each other. When we superimpose the pentacle on the color wheel, we get (clock-wise)
Purple (Spirit), Blue (Water), Green (Earth), Yellow (Air) and Red (Fire).
Though the Fire Element really falls in the color orange, for sake of traditional we'll keep it as red.
This can be another, if not artistic, view of the direction of the elements in the pentacle. One tenant of magic is that all things are connected. So keeping with this idea, why shouldn't our symbolism be connected with the visible world around us?