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