The ornamental design for a displayscreen with a graphical user interface, as shown and described.
FIG. 1 is a front view of the mobile terminal display screen with a graphical user interface.
FIG. 2 is a front view of the graphical user interface with the mobile terminal display screen shown separately for clarity of illustration.
FIG. 3 is a top view of the mobile terminal display screen with graphical user interface.
FIG. 4 is a back view of the mobile terminal display screen with graphical user interface.
FIG. 5 is a right-side view of the mobile terminal display screen with graphical user interface; and,
FIG. 6 is a left-side view of the mobile terminal display screen with graphical user interface.
In FIGS. 1, 3-6, the broken line perimeter shows the mobile terminal and forms no part of the claimed design. The dot dashed broken lines in FIGS. 1 and 2 that immediately surround the graphical user interface shows the display screen and forms no part of the claimed design.