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