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