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