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)(28,39)(29,33)(30,34)(31,38)(32,37)(36,40)(1,3,5,8)(2,6,4,7)(9,10)(11,16)(12,17)(13,18)(14,15)(19,24)(20,21)(22,23)(25,27)(26,31)(28,36)(29,37)(30,38)(32,40)(33,39)(34,35)(10,15)(13,16)(17,23)(21,24)(25,26,30,34)(27,31,38,35)(28,32,37,39)(29,33,36,40)(9,11,14,18)(10,16,15,13)(12,20,22,19)(17,21,23,24)(25,26)(27,31)(28,32)(29,33)(30,34)(35,38)(36,40)(37,39)(9,12)(10,17)(11,19)(13,21)(14,22)(15,23)(16,24)(18,20)(25,28,30,37)(26,32,34,39)(27,36,38,29)(31,40,35,33)(1,4,5,2)(3,7,8,6)(9,13,14,16)(10,18,15,11)(12,21,22,24)(17,20,23,19)(25,29,30,36)(26,33,34,40)(27,37,38,28)(31,39,35,32)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.