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