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