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