GraphQL - NodeJS vs PHP. How to choose?

Following my recent face-slap when I realized I have no personal project to submit when applying for a job, I decided to start one. Right away.

While my idea is, currently, not very well defined, I do know I want to implement some public API and present the data in an interactive way. However, the focus would be on the back-end.

Therefore, I decided to go with GraphQL. My experience with setting up a new project and choosing how to build the infrastructure is limited (read: I never did it). Hence, I'd like to ask for help to kickstart the project.

1. GraphQL means I have to choose between NodeJS and PHP. I don't have a strong opinion on any of them. Usually I'd just do what my employer / architect decides. I'm not sure which one to choose, would be a learning curve either way. However, I did notice that there seem to be a little more documentation available for NodeJS.
2. Any good advice or tutorial on how to set up everything? I know what I have to do once i get to the "write code" part. I'm a bit lost on how to get there.

Worth to mention: this is meant to be just a personal project, a playground, to learn GraphQL and to be able to submit some code next time I apply for a job.