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