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