Apple tightened its door to iOS jailbreak with the release of iOS 7.1 for iPhone, iPad and iPod touch. Therefore, there is no way to untethered jailbreak iOS 7.1 at present.
However, some developers have been working on it and want to find a way for iOS 7.1 untethered jailbreak. If you want to keep your device jailbroken and take the advantages of Cydia, please DON’T update your device unless a stable untethered jailbreak comes out
Update: A jailbreak for iOS 7.1.x is available. Get it here: http://ijailbreakguide.com/untethered-jailbreak-iphone-ipad-ipod-ios-7-1-and-above.html