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