Editing The "Free SEO Analysis" Button Color

In the 1.9 theme generation and above, this button is not a menu item anymore.

In order to edit the background color or this button, you need to edit a "Button module" from Live Composer following then next steps:

Go to WP Admin > Appearance > Headers/Footers and select the header you are using. In the case you are using the demo content, open in Live Composer the "Header - default design".
Click on the "cog icon" of the "Button module".  
Open the "Styling" tab of the module and edit the module styles. The background option is located in the "General" section.  

If you are using a theme version with Mega Main Menu plugin, follow the next instructions

Go to  WP Admin > Mega Main Menu > Skins, then scroll down.

Select  Style 1 in  Additional Styles, and change the colors in  Background Gradient (Color)