Use Microsoft Graph 5.0 SDK to get display name from listitem's LookupId field

I have retrieved an item in a list and got the field data, several of fields are users but the return value is a LookupId and I need the display name. Looking online it mainly talks about querying the site’s "User Information List" list but this is a 1.0 thing and I cannot find that list in 5.0.

How can I get the display name of a user from a LookupId value?

var doc = Task.Run(() => graphClient.Drives[driveId].Items[item.Id].GetAsync(requestConfiguration => requestConfiguration.QueryParameters.Expand = new string[] { "ListItem", "Versions" })).Result;