Please follow steps below to change the style of a cool picture (see here to transform data to cool chart):
Step 1: Click anywhere in the worksheet;
Step 2: Click the "Insert" Tab from the ribbon;
Step 3: Click "Transform cold data into a cool picture" in Add-ins section;
Step 4: In the new window, click anywhere to show buttons on the top right, then click the setting button;
Step 5: To pick a type in the "type" box;
Step 6: To pick a theme in the "theme" box;
Step 7: To pick a shape in the "shape" box.