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