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