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