What do you mean? You know you need a SATA3 cable, what else is there to ask?
If the case would work better get one with a right angle bend in the connector (or one with both right angle ends), or get one with straight connector at both ends.
Just don't get a SATA2 one and assume it will work for SATA3.
If it doesn't work (<1% chance) you may have gotten a bad cable and need to replace it. SATA cables are like HDMI cables - if they don't work it is extremely obvious, if they do they all work the same.