Please see steps below to plot sparklines from right to left:
Step 1: Select any cell with line sparklines;
Step 2: Click the "Design" tab from the Ribbon;
Step 3: Click the Axis command from the "Group" section;
Step 4: Click the Plot Data from Right-to-Left" from the drop-down list;
Step 5: You will see the sparklines are now from right to left.