NOTE: This will only work if there is not authentication in front of the API and this is using GET not all GraphQL APIs will allow GET requests.
nmap -p- -sV --script=http-grep --script-args='match="Must provide query string", http-grep.url="/graphql"' 192.168.1.137
Scan port 5013 with a list You can get the script here GraphQL nmap script then move to /usr/share/nmap/scripts
nmap --script=graphql-introspection -iL hosts.txt -sV -p 5013