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