Explanation of centralityPlot in qgraph I am using this code to get a centralityPlot. 
library(qgraph)

centralityPlot(graph2, include = 
               c("Strength","ExpectedInfluence","Betweenness","Closeness"),
               orderBy ="ExpectedInfluence")

Outcome from RStudio:

Can anyone explain what these plots mean?
What does the x-axis show?
In expected influence - does it then show -2 that they have a negative impact?
 A: Centrality plots provide information on the inter-connectedness of variables.
The x-axis shows standardised z-scores. You can change this using the 'scale' argument of the centralityPlot function:

scale 
  Scale of the x-axis. "z-scores" to plot standardized coefficients, "raw" to plot raw coefficients, "raw0" to plot raw coefficients while including 0 on the x-axis and "relative" to show values on a relative scale from 0 (lowest) to 1 (highest).

The z-score for -2 on the x-axis for Expected Influence indicates that that node has the least expected influence on the network, not that it has a negative impact.
I would be cautious of over-interpreting centrality values; see here: https://psych-networks.com/how-to-not-interpret-centrality-values-in-network-structures/
A: These are various measures of centrality for graph2, which is a graph object. The y-axis is showing each node. The nodes are ordered by ExpectedInfluence, which is why that plot increases sequentially, while the others don't really show a trend. 
