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