You need to upgrade "SEO Press" to "Pro version" to change the color of the bars.
But there is a way to change without upgrading.
Click "Editor" from the left menu "Appearance".
Click "Theme header" from the right menu.
Please insert the below tag above ＜/head＞.
Tag to change the color for the bars.
Please copy and paste.
Change the color from "red" to whatever color you want.
Use "Color chart" . Click "Update file" from the bottom.
You have changed the color of the bars.