How to change background color of a selected ItemList Material-Ui

Change default selected gray color by passing selected style like this.

<ListItem
        button
        selected={true}
        classes={{ selected: classes.active }}>
  <ListItemText primary={item.name} />
</ListItem>

Style object should be like this.

active: {
  backgroundColor: "red"
}

In your Higher Order Component add new property selectedItemStyle!

<ComposedComponent selectedItemStyle={selectedItemStyle} value={this.state.selectedIndex} onChange={this.handleRequestChange} containerHeight={this.props.containerHeight} elementHeight={40}>
   {this.props.children}
</ComposedComponent>

where selectedItemStyle is

const slectedItemStyle = {
 backgroundColor: 'red'
}

I had to use Global Theme override: https://material-ui.com/customization/components/#global-theme-override

const muiTheme = createMuiTheme({
  overrides: {
    MuiListItem: {
      root: {
        "&$selected": {
          backgroundColor: "red",
          "&:hover": {
            backgroundColor: "orange",
          },
        },
      },
      button: {
        "&:hover": {
          backgroundColor: "yellow",
        },
      },
    },
  },
});