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