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