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