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