Arduino Yun not showing anything on the serial monitor
Assuming the code works, you should be able to change the position of the servo by altering the initialized color values.  Currently they are:

 const int redPos = 160;
 const int orangePos = 130;
 const int yellowPos = 100;
 const int greenPos = 70;
 const int bluePos = 30;
 const int nonePos = 0; 


If, for example, the positions of Red and green are to be swapped all that is needed is to alter the code like this:

 const int greenPos = 160;
 const int orangePos = 130;
 const int yellowPos = 100;
 const int redPos = 70;
 const int bluePos = 30;
 const int nonePos = 0;


The numbers, according to the Arduino's servo driver web page, are the angle in degrees the servo will be moved to after executing the call to the Arduino servo driver.  

Given the above, if a new color violet were to be added to the original set of colors the first change would be to move the servo positions slightly higher to make room for the new color. 

 const int redPos = 160;
 const int orangePos = 135;
 const int yellowPos = 110;
 const int greenPos = 85;
 const int bluePos = 60;
 const int violetPos = 35;
 const int nonePos = 0; 


The next change would be to alter the ranges of the color test code.  As you did not specify what hardware you are using to detect colors, you will have to experiment to find the combination of red, green &amp; blue which matches the new color violet.  The code used for detecting blue is:

 else if ((r &lt; 0.8) &amp;&amp; (g &lt; 1.2) &amp;&amp; (b &gt; 1.2))


Likely violet contains more red and may be detectable with a line of code like this:

 else if ((r &gt; 1.0) &amp;&amp; (g &lt; 1.2) &amp;&amp; (b &gt; 1.2))


The position of this test may be important depending on how the detector works.  It may be best to place it after testing for orange.  Remember to use the new initialized variable such that you code may look like this:

else if ((r &gt; 1.0) &amp;&amp; (g &lt; 1.2) &amp;&amp; (b &gt; 1.2)){
  Serial.print("\tVIOLET");
  myservo.write(violetPos);
}