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