One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,8)(3,4,7,6)(9,10,15,19,14,20,13,21)(11,22,24,18,25,16,31,33)(12,26,28,36,29,35,30,17)(23,38,27,32,40,34,39,37)(1,3,5,7)(2,6,8,4)(9,11,14,25)(10,16,20,22)(12,27,29,39)(13,31,15,24)(17,34,36,38)(18,19,33,21)(23,28,40,30)(26,37,35,32)(1,4,5,6)(2,7,8,3)(9,12,14,29)(10,17,20,36)(11,23,25,40)(13,28,15,30)(16,32,22,37)(18,34,33,38)(19,35,21,26)(24,39,31,27)(2,8)(3,7)(9,11)(10,18)(12,23)(13,24)(14,25)(15,31)(16,21)(17,34)(19,22)(20,33)(26,32)(27,30)(28,39)(29,40)(35,37)(36,38) involution — undirected(9,13,14,15)(10,19,20,21)(11,24,25,31)(12,28,29,30)(16,18,22,33)(17,35,36,26)(23,39,40,27)(32,34,37,38)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.