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