Found a good solution... in the jqueryui.php file in the plugins, add the following before the last } in the file:
/**
* Return a (limited) list of color values to be used for calendar and category coloring
*
* @return mixed List for colors as hex values or false if no presets should be shown
*/
public static function get_color_values()
{
// selection from
http://msdn.microsoft.com/en-us/library/aa358802%28v=VS.85%29.aspx return array('000000','006400','2F4F4F','800000','808000','008000',
'008080','000080','800080','4B0082','191970','8B0000','008B8B',
'00008B','8B008B','556B2F','8B4513','228B22','6B8E23','2E8B57',
'B8860B','483D8B','A0522D','0000CD','A52A2A','00CED1','696969',
'20B2AA','9400D3','B22222','C71585','3CB371','D2691E','DC143C',
'DAA520','00FA9A','4682B4','7CFC00','9932CC','FF0000','FF4500',
'FF8C00','FFA500','FFD700','FFFF00','9ACD32','32CD32','00FF00',
'00FF7F','00FFFF','5F9EA0','00BFFF','0000FF','FF00FF','808080',
'708090','CD853F','8A2BE2','778899','FF1493','48D1CC','1E90FF',
'40E0D0','4169E1','6A5ACD','BDB76B','BA55D3','CD5C5C','ADFF2F',
'66CDAA','FF6347','8FBC8B','DA70D6','BC8F8F','9370DB','DB7093',
'FF7F50','6495ED','A9A9A9','F4A460','7B68EE','D2B48C','E9967A',
'DEB887','FF69B4','FA8072','F08080','EE82EE','87CEEB','FFA07A',
'F0E68C','DDA0DD','90EE90','7FFFD4','C0C0C0','87CEFA','B0C4DE',
'98FB98','ADD8E6','B0E0E6','D8BFD8','EEE8AA','AFEEEE','D3D3D3',
'FFDEAD'
);
}