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