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