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