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