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