I installed libX11 (yum install libX11) which resolved the chromedriver execution issue. However, here is the new error message I receive when trying to invoke a report from the UI:
{"type":"ApiError","message":"unknown error: Chrome failed to start: exited abnormally\n (unknown error: DevToolsActivePort file doesn't exist)\n (The process started from chrome location /usr/share/graylog-server/bin/headless_shell is no longer running, so ChromeDriver is assuming that Chrome has crashed.)\n (Driver info: chromedriver=72.0.3583.1 (9ae827a6f6bbc9186d4e79681de885ce77d5bfe9),platform=Linux 3.10.0-957.5.1.el7.x86_64 x86_64) (WARNING: The server did not provide any stacktrace information)\nCommand duration or timeout: 67 milliseconds\nBuild info: version: 'unknown', revision: 'unknown', time: 'unknown'\nSystem info: host: '<HOST>', ip: '<IP>', os.name: 'Linux', os.arch: 'amd64', os.version: '3.10.0-957.5.1.el7.x86_64', java.version: '1.8.0_191'\nDriver info: driver.version: RemoteWebDriver"}