Creating your own custom Sign In With Facebook button

let loginButton = FBSDKLoginButton()
loginButton.delegate = self
// Your Custom Permissions Array
loginButton.readPermissions =
[
                         "public_profile",
                         "email",
                         "user_about_me",
                         "user_photos"
]
// Hiding the button
loginButton.hidden = true
self.view.addSubview(loginButton)
// Simulating a tap for the actual Facebook SDK button
loginButton.sendActionsForControlEvents(UIControlEvents.TouchUpInside)

FBSDKLoginButton *FBButton = [FBSDKLoginButton new];

// Your Custom Permissions Array
FBButton.readPermissions = @[@"public_profile",
                             @"email",
                             @"user_about_me",
                             @"user_photos"
                             ];
FBButton.loginBehavior = FBSDKLoginBehaviorNative;
[FBButton setDelegate:self];
[FBButton setHidden:true];
[loginButton addSubview:FBButton];

[FBButton sendActionsForControlEvents:UIControlEventTouchUpInside];