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