Your question is about information design.
First, if this topic interests you greatly, I recommend you find The visual display of quantitative information by Tufte. His books are beautifully illustrated but expensive—so check your local library first or get your employer to buy you this book. Tufte will get you thinking about the design of charts and graphs in all sorts of clever ways.
Second, information-design problems such as this benefit from iteration. Try sketching five or more distinct solutions to this problem. You can probably do better than what I'm about to suggest. I'll repeat and add to this, below.
Third, here's my "next draft" of your iteration:
- Rotate the left side by 90°, such that negative = down and positive = up.
- Match the colours on the left side and right side, so one colour can show differing values of the same attribute.
Here's an illustration of this idea:
Lastly, let me re-iterate: I have no doubt you can improve on my suggestion, and you can come up with additional ideas of your own that are better. I can't overemphasize the benefit of sketching, with a pen on paper, five or more distinct solutions to this problem. [Edit: As @Nightning notes, make sure you know what information users need.—See comment.] They key is to generate the ideas without critiquing. There may be a sticking point after the first two or three sketches. Keep going. Once you have five or more ideas, mash them up and identify any weaknesses, and then sketch again. So first it's a generative/creative stage—without judging—and next it's a separate, analysis/mash-up stage. Repeat as needed. It's hard work to come up with good ideas, but rewarding.
And one more thing…. This is excerpted from a UIE post on effective data visualization, which confirms you're on the right track:
- Clear purpose – Define what you want the infographic to do for your users.
- Relevant content – Trim anything extraneous and distill what’s left down to its essence.
- Appropriate structure – Choose the most effective way to display your data and consider its physical placement on the page.
- Useful formatting – Make informed choices about fonts, colors, typography, labels, tool tips, and icons.