You can't do that.
The keyboard was designed to illuminate like that.
All keyboards with cherry MX compatible RGB switches will look like this.
Cherry MX RGB switches have clear housings so the light can diffuse through the switch, and these keyboards have white painted metal backplates, so the light reflects better (exactly what you seem to NOT want).
The only keyboard that will give you the lighting you are asking for (legends only) is the Logitech G910 Orion Spark (and maybe the 430 or whatever that cheaper one is called), but those aren't cherry MX compatible switches or keycaps and willi require LGS software to change the lighting (the software must be active in memory).
Now you may be able to mod the keyboard to have only the legends emit light, however you would have to first of all, paint the backplate completely black with a custom paint job (assuming you know how to paint small surfaces), which I assume would be a bit of work. Then you would have to find a way to block some of the light diffusion coming from the transparent switch housing which would require you painting over part of the switches in such a way that you don't completely destroy the switch's ability to put light through the keycaps, as that would not likely be a reversible process. And even if you successfully did it, it's hard to say what the outcome would be.
If you're going to try some crazy mod like this, I suggest you order this keyboard through a taobao agent:
http://world.tmall.com/item/44626454261.htm?spm=a1z10.1-b.w5003-10672047312.1.8BYdZC&id=44626454261&scene=taobao_shop&skuId=3121294889790(button #4 on the lined up keyboard pictures is the RGB version you would want)
and then use something like this to buy the keyboard.
http://www.youdobuy.com/taobao-agent-product-detail-customerized_44626454261.htm (button #4 again)
or
http://www.engtaobao.com/ http://www.engtaobao.com/item/44626454261.htmlThey do have a non RGB fixed color LED (87 key tenkeyless) Zhihue change it yourself keyboard, but you probably want RGB if you want to practice modding like that.
The keyboards (and I think the cheaper 87 key change it yourself version although I'm not sure if its the same one:
http://world.tmall.com/item/524142355125.htm?id=524142355125&ali_refid=a3_430582_1006:1109657747:N:机械键盘 87:6abb9f3d860db6ff4d8bf085df7fd28c&ali_trackid=1_6abb9f3d860db6ff4d8bf085df7fd28c&spm=a230r.1.14.1.9j0NJi&sku_properties=5919063:6536025)
But the whole point is so you can practice painting switches that you can buy, like Gaterons/Zeals then put them on the keyboard and swap them until you figure out how to paint a switch with 100% reliability, before moving to the Corsair Strafe, which would be a non reversible job (and you can't swap the switches without soldering).
It would be a very tedious job but I guess you have to do it if you expect results....