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