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