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