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