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