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