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