This is currently the strongest version of a Xayah carry comp with Talon as a secondary carry as well. This comp can be a nice choice as you have two different ways to go about transitioning, either with Assassins or with Swiftshot units.
When to make
Go for this comp if you have a lot of good AD items (Bows and Swords), and have a decent start with either Assassin, Ragewing, or Swiftshot units.
How to play
This comp uses the standard leveling strategy that revolves around a 4-cost carry.
Early Game Plan
Mid Game Plan
Additional comp tips
Even though Sejuani is in the comp, you don't necessarily have to pair her with a Cavalier in the early game. You can simply use her for the Guild bonus for the team. The same thing goes for Twitch, but a Swiftshot like Ezreal is a nice pair to have. If you can reach level 9 - make sure you throw in Bard as a high cost and value CC unit, but also to increase the Guild bonuses.