One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,7)(4,5)(6,8)(9,10)(11,16)(12,17)(13,18)(14,15)(19,23)(20,21)(22,24)(25,26,31,34)(27,30,29,33)(28,37,39,32)(35,38,36,40)(2,5)(6,7)(10,15)(12,21)(16,23)(18,22)(25,27,31,29)(26,30,34,33)(28,36,39,35)(32,38,37,40)(1,2)(3,6)(4,5)(7,8)(11,19)(13,24)(16,23)(18,22)(25,28,31,39)(26,32,34,37)(27,35,29,36)(30,40,33,38)(1,3)(2,6)(4,8)(5,7)(9,11)(10,16)(12,22)(13,20)(14,19)(15,23)(17,24)(18,21)(25,28)(26,32)(27,36)(29,35)(30,38)(31,39)(33,40)(34,37) involution — undirected(9,12,14,21)(10,17,15,20)(11,18,19,22)(13,23,24,16)(25,29,31,27)(26,33,34,30)(28,36,39,35)(32,38,37,40)(9,13)(10,18)(11,20)(12,23)(14,24)(15,22)(16,21)(17,19)(25,30,31,33)(26,27,34,29)(28,38,39,40)(32,36,37,35)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.