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