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