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