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