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