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