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